Small model packs, STOOLS, addons generally under 10MB can be downloaded from your server without risking alot of lag on player join. As the above poster, posted PHX is too big and clients should have it on theit PC’s anyways since its a very popular addon.
Other larger addons like SBEP, Stargate, Vehicle packs, and the like also should not be downloadable through your server.
If you have alot of custom addons then set up a fast DL server especially for your maps.
You can state in your MOTD what addons your running and some links to said addons so people can go get them.
My server has alot of addons BUT my MOTD instructs players to go download the bigger things so they wont have errors all over.
Custom models and textures can be passed from your server also if you set up the files to do so and they are not alot of files. People do not like to sit and wait for ages for files to download.